NEW YORK (CNN) -- One of America's pre-eminent political power couples made a rare joint appearance Friday, when Bill and Hillary Clinton took the stage at the former president's Clinton Global Initiative conference.

Bill Clinton says his wife Secretary of State Hillary Clinton is the "best public service our family has ever produced."

"I want to begin by expressing my extreme indebtedness to the Clinton Global Initiative, to all of you who participated, for giving me the first chance I have had in a week to see Hillary," Bill Clinton told the audience of social activists and business leaders at the closing session of CGI, a week-long conference designed to find solutions to global problems through public and private partnerships.

Secretary of State Hillary Clinton was at the session to unveil a new State Department initiative on food security.

As he introduced her, the former president was effusive in his praise for his wife, saying that her approach to food security -- helping farmers around the world grow their own food to earn income and alleviate poverty -- was much smarter than the decades-long policy of simply giving humanitarian aid and food to countries. Watch Clinton pay tribute to his wife »

"Most of what I know about what I do today, I learned from her and she has become the best public servant our family has produced," he added. "I am very proud of her and honored that she came here."

Hillary Clinton, who received a standing ovation, had equally kind words for her husband.

"It won't surprise you to hear that I am very proud of my husband, and I think what he has invented and brought to life here is extraordinary," she said, adding that the new State Department food initiative, in part, was an idea she developed by seeing the kinds of partnerships the Clinton Global Initiative produced.

The Clintons posed for a photo-op with State Department officials and executives from General Mills and other organizations, who pledged at the conference to start a program to help farmers around the world.

And then, for fans of the former first couple, a rare treat. As she walked off the stage, Bill Clinton drew some more cheers when he gave his wife a kiss.

Bill Clinton continued to read off the million-dollar commitments he received at the conference for additional social programs. Hillary Clinton left to meet with 15 ministers from the Caribbean.